Polypeptides obtained from eukaryotic cells are produced as glycosylated polypeptides. The glycostructures are attached to the amino acid backbone as post-translational enzymatic modification.
The glycosyltransferases are recognized as a functional family of estimated 250-300 different intracellular, membrane-bound enzymes that participate in the coordinate biosynthesis of the glycostructures of polypeptides, including glycoproteins, proteoglycans and glycolipids. The glycosyltransferases are classified into groups based on their nucleotide monosaccharide donor specificity. For example, the galactosyltransferases are the subset of glycosyltransferases that use UDP-galactose as the activated monosaccharide donor whereas the sialyltransferases use CMP-sialic acid and the fucosyltransferases use GDP-fucose (Shaper, N. L., et al., J. Mamm. Gland Biol. Neopl. 3 (1998) 315-324).
A method for clinical examination based on the structures of immunoglobulin G-linked oligosaccharides is reported in EP 0 698 793. In EP 1 878 747 glycoengineered antibodies are reported. Selective marking of immunoglobulin glycans is reported in WO 2007/071347. In WO 1997/016064 methods and compositions for the reduction of xenotransplantation rejection are reported. Antibody preparations with substantially homogeneous and non-sialilated glycostructures, such as G0 and G2, which are prepared by enzymatic treatment, expression under certain conditions, use of particular host cells, and contact with serum, are reported in WO 2007/024743.
In WO 2008/057634 polypeptides with enhanced anti-inflammatory and decreased cytotoxic properties and relating methods are reported. Proteolysis resistant antibody preparations are reported in WO 2007/024743.